Replaceable fluidtight filter holder



Sept 3, 1963 aL/15H 3,102,741

REPLACEABLE FLUIDTIGI-IT FILTER HOLDER Filed Nov. 1s, 1959 #Trans/5VUnited States Patent() The invention described herein may bemanufactured and used by or `for the Government of the United States ofAmerica for governmental purposes `without the payment of any royaltiesthereon or therefor.

This invention relates to a replaceable, fluidtight filter holder andespecially to a replaceable, -fiuidtight filter holder for 4use withimpermeable clothing.

There are circumstances in the military service and 1n the industrialsphere which require that `personnel be protected from toxic gases `andhighly corrosive vapors or liquids. For protection against such hazards,some type of protective suit, usually made of a coated rubberized fabricimpermeable to moisture vapor and air, is generally provided. Such suitsare supplied with air either through a -portable air supply carried bythe wearer, a hose connected to a fixed air supply, or Ventilatingopenings in the suit.

Of course, such Ventilating openings must be covered by filters whichare capable of absorbing the toxic gases and corrosive vapors that maybe encountered. The filters must be attached to the suit in a iiuidtightmanner and it is extremely desirable that the filters be easily andspeedily removable and replaceable.

In the present invention, these functions are accomplished by a4two-section filter holder, one section being secured penmanently to thesuit and the second section being easily removable from the first. Thesecond section` carries the filter and makes fluidti-ght contact withthe first section lwhen the two sections are assembled in workingcondition.

An object of this invention is to provide an easily replaceable,iiuidtight filter holder for use with protective envelopes orincasements which are impervious to gases and vapors.

Other objects and many of the attendant advantages of lthis inventionwill be readily Vappreciated as the same becomes better understood byreference to the lfollowing detailed description when considered inconnection with the accompanying drawings wherein:

FIG. l is a perspective view of the removable section of a filterholder, showing a preferred embodiment of the invention;

FIG. 2 is a perspective view of the fixed section thereof; and

FIG. 3 is a cross-sectional View of the embodiment shown in FIGS. 1 and`2 taken along the lines 3 3 and 33.

Similar numerals refer to similar parts throughout the several views.

The invention comprises two sections, the replaceable section whichcarries the filter being shown in FIG. l and the section which isafiixed to the impermeable suit, or other incaseiment, being shown inFIG. 2. The fixed section 12 has a disc-shaped base, or flanged portion14, from the inner edge of which rises a circular wall 16. This fixedsection 12 may 'also be visualized as being constructed from a disc (thebase) and a hoop (the wall), the hoop being attached to the inner edgeof the disc.

The base -14 of the fixed section 12 has a fiat bottom 13 to which theedges of an excised portion of the impermeable suit may be cemented withany suitable cement which is impervious to fluids and corrosive vapors.The shape of the excised portion of the suit may preferably be circular,corresponding in area to the circular ICC central opening 18 which isencompassed by the wall `16. The outer surf-ace 20 of the wall 16 isformed with an excised portion `22 which covers a considerableex.- tentof fthe distance between the top 23 of thewallq16 and the base I14. Theshape of Vthe opening 18f encompassed by 4the -wall 16, and therefore ofthe wallitself, is shown-here as circular although obviously, it is notnecessarily `limited to this particular` lgeometrical configuration butmay be square or rectangular, etc.

The outer surface 2li of the wall 1-6 and the `correspending surface ofthe -wall within the excised portion 22 are tapered with the peximetricdimension (thelong dimension comprising a circle around t, the surfaceof the wall) increasing from the top of the wall to the base 14. p Aloop, or 4O ring, 24 of resilient material impervious to iiuids andcorrosive vapors, such `as rubber, is fitted into the `excised portion22 of the wall 16. Thewlnormal inner diameter of` this loop .24corresponds to the` perimettric dimension ofthe upper, ornarrower, partofthe excised portion 22 so that the loop 244 must bestretched to bring`it down toward the base and it tends to return to the upper part of theexcised portion `22Vwhen no downward `force is exerted upon it. Thecross sectional area of the loop 24 is large enough so that the loop t24 projects past the outer surface `20 of the wall 16.

The replaceable section .26 of the invention isshown in PIG. l andconsists of `a disc-shaped base, orflanged portion, 28, a wall `3i)rising `from -the inner `edge of the base 28 and a flange 32 extendinginwardly from the top of `the Wall 30. The topl surface of the flange'32is iiat and the filter can be cemented thereto with any suitable cementwhich is impervious to lfluids and corrosive vapors, the filter may alsobe `afxed to the lower surface of the iiange 32 or to the inner surface34 of the wall 30 by any other suitable means, if so desired. The filterholder sections 12 and 26 are fabricated from a material which is rigidand impervious to liuids and corrosive vapors, for example, fiber-glassreinforced plas- (tic. Many plastics may be utilized, la satisfactoryone being polyester plastic. Other materials which .may be used includevarnished wood and various metals, especially in applications where theenvironment will not` contain corrosive vapors.

The inner surface 34 of the Wall 30 is tapered somewhat more sharplythan the outer surface 20l of the wall 16. 'Typical degrees of taperwould be two degrees from the vertical for the fixed-section wall 16-and tive degrees for the replaceable-section wall 30.

The base 28 of the replaceable-section wall 30 carries the male members36 of four Dzus fasteners spaced at degree intervals; the base 14carries the female members 38 at corresponding intervals. Any otherconvenient means Iof removably clamping together the two sections of thefilter holder may also be used; for example, four horizontal pegs, orspikes, might extend from the surface 40 near the top of thefixed-section wall 16 to. slide into correspondingly placed verticalgrooves in the inner surface 34 of the wall 30 when the replaceablesection 26 is forced down upon the fixed section 12 in the positionshown in FIG. 3. A series of closely spaced horizontal groovesconnecting with each vertical groove would allow the replaceable section26 to be twisted slightly so that it could be locked in place when thedownward limit of its movement is reached. This would comprise abayonet-type clamp.

When the filter holder is assembled, the replaceable section `26 ispressed down upon the iixed section 12. The difference in the degree oftaper of the surfaces 2l) and `34 causes the loop 24 to be forceddownward and tightly compressed between the inner surface 34 of theyreplaceable-section Wall 30 and the sulface of the eXcised portion 22iof the fixed-section Wall 16. This effects a tiuidtight closure betweenthe two filter-holder sections. The Dzus fasteners are then closed so.that the two sections are held together securely. The difference in thetaper of the VWalls permits automatic compensation for variable factorssuch as wearing of the loop 24 or varilation's'in size o-f the Xed andreplaceable sections.

Whenthe filter carried by the replaceable section 26 is no longereffective in its filtering action, the Dzus fasteners areV opened, thereplaceable section 26 is removed and anew replaceable section with anunused filter is subf stituted for the old one. The entire operation canbe accomplished within a feW seconds.

vObviously many modifications and variations of the `present inventionare possible in 4the light of the above teachings.` It is therefore tobe understood thatl `within the scope `of the appended claim theinvention may be practicedotherwise than as specifically described;

' I claim:

l "A, replaceable, iiuidtight filter holder comprising, in

combination: a first section of rigid, Huid-impervious material having abase and a flange rising therefrom, said flange having an outer surfaceyand an inner surface encompassing a central opening, the outer surfaceof said flangey being, tapered .so that its long perimeter increasestoward said base and being formed with an undercut between., ,said baseand thetop of said flange, said undercu't' extending completely aroundthe long perimeter of said flange and having a smooth tapered surface,the taper being similar to that of said outer surface; an elastomericO-ring of'uid impervious material placed in said undercut and'closelyencircling the tapered surface ofthe undercut adjacent its smallerdiameter in sealing relation thereto, andi-O-ring hav-ing across-sectional diameter greater than the depth of said undercut, ands-aid O-ring being movable along said undercut with a rolling motion; asecond section of rigid, fluid-impervious material having a base and awall rising therefrom, said rwall being of lesser axial extent than saidflange and having an inner surface encompassing a central opening andcorresponding in perimetric shape to that :of the outer surface of saidrst-section flange but having a slightly greater taper so that when saidsecond section is fitted over said first section with said bases beingmade to Vapproach each other, said resilient loop is moved at 'least tothe point at which the outer perimetric dimens-ion of the undercutequals the normal inner perimetric dimension of said O-r-ing and saidO-ring is tightly compressed between said inner surface of saidsecond-section wall and said undercut flange =of said first sectionthereby forming a iiu-idtight closure, the axial length tof saidundercut being sutiicient to permitv free rolling action of the -O-ringalong the undercut during assembly of said two sections; and means onsaid base members for removably fastening said secv tions to each otherwhen they are fitted together to provide said fiuidtight closure.

References Cited in the file of this patent UNITED STATES PATENTS

